Field of the Invention
The present invention relates to a toner to be used in an electrophotographic method, an electrostatic recording method, and a toner jet type recording method.
Description of the Related Art
As a toner for an improvement in low-temperature fixability and storage stability of the toner, there is a toner particle having a core-shell structure in which the surface of a resin serving as a core is covered with a shell resin.
Furthermore, a method involving using a hydrophobic material that is hardly affected by a temperature and a humidity as the shell resin covering the surface of the toner particle is conceivable as a method of improving the environmental stability of the toner. An organopolysiloxane has been known as a material having low interfacial tension.
Therefore, the introduction of an organopolysiloxane structure into the shell resin of the toner particle is expected to be capable of imparting charging performance that is not affected by a humidity.
However, the glass transition point (Tg) of the organopolysiloxane is generally lower than room temperature. Accordingly, when the organopolysiloxane is present in a large amount in the shell resin, the surface of the toner particle softens and hence the durability of the toner reduces. Accordingly, it is important to control the introduction amount and state of presence of the organopolysiloxane.
In Japanese Patent Application Laid-Open No. 2006-91283, there is a proposal of a toner particle having a core-shell structure, the toner particle containing an organopolysiloxane compound in each of a core resin and a shell resin. The evaluation of a toner produced based on the disclosure has confirmed that the toner has a suppressing effect on fluctuations in charging performance due to a high-temperature and high-humidity environment, and a low-temperature and low-humidity environment.
In Japanese Patent Application Laid-Open No. 2010-132851, there is a proposal of a method of producing such a toner particle that a resin fine particle is fixed to, or is formed into a film on, its surface. In the method, carbon dioxide in a liquid state or a supercritical state is used as a dispersion medium, and a toner particle is formed in the dispersion medium having dispersed therein the resin fine particle and a compound having a dimethylpolysiloxane group serving as a dispersion stabilizer. Thus, a toner particle having the resin fine particle fixed to its surface is obtained.
In Japanese Patent Application Laid-Open No. 2010-168522, there is a proposal of a method of producing a toner particle having a resin fine particle adhering to its surface. In the method, carbon dioxide in a liquid or supercritical state is used as a dispersion medium, and a toner particle is formed in the dispersion medium having dispersed therein a resin fine particle formed of a silicone resin. Thus, a toner in which the resin fine particle adheres to the surface of the toner particle is obtained.
In Japanese Patent Application Laid-Open No. 2013-137495, there is a proposal of a toner particle having a core-shell structure in which a shell layer based on a resin containing the organopolysiloxane structure is formed.
The toner particle is produced by using a resin fine particle containing the resin containing the organopolysiloxane structure and by using the same method as that of Japanese Patent Application Laid-Open No. 2010-168522, and the optimization of the amount of a segment having the organopolysiloxane structure present in the surface of the toner particle can achieve both environmental stability and durability.